how to calculate the transaction size

[sheree]

Hello guys
I read about fees and it should be changed according to the transaction size
so I want to know how to calculate the transaction size.

[Alaki]

As reported in the Bitcoin Wiki, every 1,000 bytes of data in a transaction adds 0.1 mBTC to the fee. Any size below an even thousand is rounded up to the nearest thousand. For example, the fee on a 675-byte transaction would be 0.1 mBTC. Likewise, the fee on a 1,345-byte transaction would be 0.2 mBTC.
To estimate a fee, we need a way to relate the number of transaction inputs (in) and outputs (out) to it's size in bytes (size). The exact size of a transaction can only be determined after it has been signed, which is unfortunately too late to be of much use in many wallet programs. However, the upper size limit can be
found with this equation:

Code:

size = 181 * in + 34 * out + 10

[]-> http://bitzuma.com/posts/making-sense-of-bitcoin-transaction-fees/

-> https://bitcointalk.org/index.php?topic=1337040.msg13649781#msg13649781

[Outlander]

For the most Bitcoiners,they wouldn't know this! But what we normally do is to set the amount of fees / byte included in the transactions in our wallets. Most of the desk wallets are offering this features. So it will be easy for us no need to go through the complex formula.

[ranochigo]

As reported in the Bitcoin Wiki, every 1,000 bytes of data in a transaction adds 0.1 mBTC to the fee. Any size below an even thousand is rounded up to the nearest thousand. For example, the fee on a 675-byte transaction would be 0.1 mBTC. Likewise, the fee on a 1,345-byte transaction would be 0.2 mBTC.
To estimate a fee, we need a way to relate the number of transaction inputs (in) and outputs (out) to it's size in bytes (size). The exact size of a transaction can only be determined after it has been signed, which is unfortunately too late to be of much use in many wallet programs. However, the upper size limit can be
found with this equation:

Code:

size = 181 * in + 34 * out + 10

[]-> http://bitzuma.com/posts/making-sense-of-bitcoin-transaction-fees/

It is not always accurate due to a variety of factors. Most clients calculate this automatically for you. The fee is not 0.1mBTC/kb, it can be as low as 0mBTC or 0.05mBTC/kb for non-free transactions.

Your information is also out of date. The equation you posted is out of date, it uses uncompressed key which is not what most wallets implement right now. Compressed keys uses this equation

Code:

 134byte*/input+ 32byte/output*

. This is not quite accurate and can vary for various transactions.